Electron tube



l-l.12,1935.y f KQKOHL 1,991,232

ELECTRON TUBE Filed April 6, 1952 2 Sheets-Sheet 1 Feb. l2, 1935. K KQHL` 1,991,282

ELEcTRoN TUBE Filed April 6, 1932 2 Sheets-Sheet 2 Jzwezdar.'

Kaff] /a/Z Patented Feb. 12, 1935 f 'UNITED' vs'rii'rtzs ELECTRON n l Karl Kohl, IErlangen,"Germany sclaims. (crest-21st second electrode may also be termed the grid elec# trode,-but it mustl be borne in mind that it has v nothing in common with .the control gridsof the` l-Oy ordinary electron tubes. Further, a third electrode is provided, the so-called braking electrode, which has a 'small voltage relatively: to rthe grid electrode. The emission lof electrons from the lcathode is accelerated' by.,rv the grid electrode. l;y Afterv passingfthrough the v'gridelectrode the ac-v celeration ceases andan auxiliary deceleration.

y or abrakin'g of the speed ofthe electrons occurs due to the auxiliary electrode,. thebraking electrode. This third electrode'can be replacedin an equivalent manner by a magnetic field.y In

this vway the sameeiectis"attainedfin principle as Awith the braking electrode which has a small volt; age relatively tothe grid electrode.v The tube is connected in the oscillation circuit so 'as to' produce oscillations as one of the natural-'frequencies thereof, the 'grid electrode acting 'as a self-induction -in this'circuit.`

Y In particular the invention isconcerned with a.

denite constructionfof the grid electrode of the tubes described' above. The new grid is so constructed that it consists of a number' of helically extending coils of Wire Which'are arranged coaxially and interpenet'rating; vAs the frequency of the waves emitted isdetermine'd` substantially by the grid-electrode and as it has further been found to -be advantageous in order, to avoid inhomog'eneities inthe eld, to wind the grid electrode'as densely as possible, the mode of winding in accordance with'the present 'invention affords the possibility-of constructing a `grid with partici ularly small -selfeinduction which iis not possible in the case ofJ-simple wound helices which have hitherto been used as grid. The mode ofgrid winding can be used advantageously with the various oscillation aggregates with Whichit is possible to transmit short waves. s

'I'he grid arrangement according to the invention can be used with the same advantage for oscillation circuits of the di-pole construction, as also for oscillation circuits coupled with a Lecher system as well as in an oscillating system consisting of a grid coil the ends of which are short-circuited'by a yoke. In all these oscillation systems the advantages of the smaller self-induction are operative. If an oscillation aggregate with a short-circuited yoke is used then'accordingv 110 `the further development of the invention it is possible `to short-circuit this yoke either inside or outside Y thetube. u f, f

11 Further it fails, within theambit ofthe invention touse double. helices of varying form, for example, in lthat one windingisof `a smaller diamer thanthefotherqand that one Aof the twocoils I` has` a larger or. smaller number of v,turns than the other. Finallyit is also'possiblefor each helix which is provided to be short-circuited separately by imean's'of arshortcircuit'yoke. Inthis way it is,'for example; possible to :sub-divide the emission stream so'as toJobtainfla further modulation of theishortwaves.; Herefalso, each ofthe short circuitjyoke's `mayj bey short-circuited' either inside or outsidetheltube. Y

It should also be noted' that the grid may be subdivided into three orY more individual helices instead of; two. In thesubsequent'descriptiom as in the drawings, only the sub-division'of the grid intok two 'helices willV be discussed.

. Certain. embodiments `of the invention-are cle--` scribed in greater detail `with reference to the. acv companyingdrawin'gsin whichcf Fig. 1 showsa tube in .perspective in which the braking electrode is partlycut away vso that the double arrangement of the gridhelices isapparent.'`

. Fig. 2 shows the same arrangement but in schematic representation inorder'to maker it more readily understood.

v Fig.. 3 showsv a grind winding in whichthe"diam eterjof one' helix islarger than that of the other Fig.Y 6 shows the useof the grid in an oscillation aggregate inthe-formfof a Vdi-pole. f y f 'f Fig. 7 shows the arrangement of the grid in anl oscillation aggregate to which is coupled a Lecher f system to the ends of which di-poles are coupled and it should be borne in mind that the particular modes of winding the coil shown in Figs. 2 to 5 could also be used in Figs. 6 and 7,- and Fig. 8 is a perspective view of the tube showing modied details,

In Figs. 2 to 6 the question as to how the ends of the grid are short-circuited has been left open.

In the perspective representation of Fig. 1 the grid arrangement is furnished with a short circuit yoke. vAt the same time attention must be' d irected to the fact that in this case the retarding field is created by means of an auxiliary electrode (the braking electrode) whereas it is also possible in known manner to generate the retarding eld by a suitable magnet arrangement.

is the glass bulb of the tube which is mounted on a base 11. The cathode 13 is carried on a. supporting yoke 12 with corresponding connections passing through the base. The grid also is held in position by means of a yoke 15 by way of a corresponding supporting device 16. In accordance with the invention the grid is subdivided'into two helices 17 and 18. In this embodiment the two ends of the helices are closed by the yoke 15. However the connection to the yoke 15 might not be effected byway of the wire 16 and it would also be possible, for example, for the grid yoke to be left open within the' tube and omitting the connection 19 to lead the ends out to the outside by way of two wires, the connection thenbeing provided outside the tube, as Ashown in Fig. 8. The braking electrode 22 can also be carried on a supporting wire 23 which can be passed through the base of the tube at 24.

In'the embodiment shown the arrangement comprising the cathode, grid electrode and the braking electrode is disposed horizontally within the tube. Obviously the entire arrangement could be rotated through 90"` or accommodated in other positions within the tube.

For the sake -of clarity the grid helix is again shown schematically in Fig. 2 from which it can. be clearly seen that the helices 17 andv 18 are arranged co-axially andinterpenetrating, the two helical windings having the same diameter.

A second arrangement'is shown in Fig. 3 in which the helix 18 is of greater diameter than the helix 17..

In Fig. 4 vthe outer helix 18 has fewer turns than the inner helix 17. If desired, the arrangement may be the inverse.v

In Fig. 5 the unitaryconnection ofV the two helices as shown in Figs. 1 to 4 is divided. 'I'he further connections 15a and 15b .can be separately short-circuited, for example, by means of a yoke or can-be connected each separately to a di-pole or coupled with a Lecher system. Cor responding to Figs. 3 and 4 the helices shown may have separate connections exactly as shown in Fig. 5. These arrangements are not shown separately in the drawings as they can be readily understood.

If the Voscillation circuit of Fig. 1 which is shown with a short circuit yoke is replaced by an open oscillation aggregate according to Fig. 6 then a di-pole is obtained. For this purpose it is only necessary to continue rectilinearly the extensions 23 and 24 of the grid electrode. The length of this continuation is determined in accordance withv the wave-length emitted. The total length of the Oscillation aggregate is M2.

to correspond to a node.

ydicated schematically in the gure.

The line 25 indicates schematically the oscillation in the open oscillation aggregate.

In Fig. 7, the grid electrode according to the application is used in the so-called Lecher circuit. The grid connections 15 are led out through the glass bulb. The lead-through wires 21, 22 are bent at their free ends to form a di-pole. The lengths of the lead-through wires are also determined in accordance with the wavelength. In this gure also, the wave is indicated schematically by 25. From this it will be seen that there is a point of maximum amplitude (anti-node) at each end of the grid. The points of bending 30, 31 are preferably so disposed as The total length of the connected di-pole also amounts to M2 as in- Preferably the wires 21, 22 approach each other towards their ends in order to prevent instability of the di-pole. Further a condenser 29 can be included in the di-pole. f

1. Improvement .for generating ultra-short electrical waves on the Barkhausen-Kurz principle, comprising a cathode, a braking electrode, and coaxial helical coils adapted to be` applied with equal high positive voltage vand connected in parallel for the ultra-short waves, said helixes being connected together with each other at their ends.

2. Improvement for generating. ultra-short electrical waves on the Barkhausen-Kurz principle, comprising a cathode, a braking electrode, and coaxialV yhelical coils adapted to be applied with equal high, positive voltage and connected in parallel 1 for` the 'ultra-short waves, said helixes being connected together with each Aother at their ends andforming a tuning system together with rthe outer electrical connections.'

3. Improvement for generatingr ultra-short electricalk waves' on the Barkhausen-Kurz principle, comprising Ya cathode, a braking electrode, and, coaxial helical coils adapted to be applied with equal high positivevoltage and connected in parallel for the ultra-short waves,.said helixes being connected together with each other at their ends and forming a tuning system together with the outer electrical connections and lthe helixes each having the same number'of turns.

4. Improvements for generatingV ultra-short electricalwaves according to claim j3, in which the helixes have the same diameters.

5. Improvements for generating ultra-short electrical waves according to claim 3, in which the helixes have different diameters.

6. Improvement for generating ultra-short electrical waves on the Barkhausen-Kurz principle, comprising a cathode, a braking electrode, and coaxial helical coils adapted to be applied with equal high positive voltage and connected in parallel .for the ultra-'short waves.

KARL KOI-IL 

